Antiplatelet Therapy for Every Diabetic Person?

Until recently, aspirin was recommended by most guidelines for the primary prevention of cardiovascular events in people with diabetes. Recommendations were primarily based on indirect evidence from large trials of populations at high risk of cardiovascular (CV) events. Evidence supporting the efficacy of aspirin therapy in trials of diabetic subjects only is scant. A previous meta-analysis on the efficacy of antiplatelet therapy in the prevention of major CV events found a clear benefit of aspirin overall, but no statistically significant benefit in the subgroup of people with diabetes. No significant reduction in the risk of major CV events with low dose aspirin compared with placebo was found in three additional trials published after that meta-analysis. New meta-analyses incorporating the results of more recent trials agree in indicating that the use of aspirin is associated with a 10% reduction in the risk of major CV events, with no significant effect on CV or all-cause mortality. A differential sex effect is also suggested. The lowerthan-expected benefits of antiplatelet therapy make particularly important the evaluation of the risk-benefit balance. Aspirin use is associated with an excess risk of major bleedings of one or two cases for 1,000 individuals treated for 1 year. Such a risk is even higher in the real world setting, exponentially increases with age and is probably increased in the presence of diabetes. Given the currently available limited evidence, it seems reasonable to suggest aspirin treatment only for patients with a 10-year risk .15%, and without contraindications for aspirin. CV disease (CVD) is the leading cause of morbidity and mortality in patients with diabetes (1). In addition to the concomitant presence of multiple classical CV risk factors that increase atherothrombotic risk (2), diabetes is a “prothrombotic state” associated with accelerated atherosclerosis and inflammation that contribute to the pathogenesis and progression of vascular complications (3). For this reason, interventions to block one or multiple pathways modulating platelet activation and aggregation processes are considered as an essential component of diabetes care to reduce ischemic risk (4). The use of aspirin for secondary prevention of CV events in patients with coronary or cerebrovascular disease is well established and is supported by solid evidence from the Antithrombotic Trialists’ (ATT) Collaboration meta-analysis (5). This meta-analysis found that aspirin was beneficial in patients with previous myocardial infarction (MI) or stroke or transient cerebral ischemia. In these high risk populations, aspirin decreases the risk of future events by about onefifth. In contrast, the role of aspirin for primary prevention of CV events in individuals with diabetes is controversial, and the debate has been recently refueled by the publication of the results of two randomized clinical trials and several meta-analyses. In this review, we will examine the pros and cons of aspirin use in the primary prevention setting in individualswith diabetes.